“It’s not until they tell you you’re going to die soon that you realize how short life is,” Stefansson said at the time, per the BBC. “Time is the most valuable thing in life because it never comes back. And whether you spend it in the arms of a loved one or alone in a prison cell, life is what you make of it. Dream big.”

Stefansson, who is survived by his wife and four children, shared this quote in his final Instagram post last June:

Fans of “LazyTown,” which ran from 2004 to 2007 and 2013 to 2014, used memes of Stefansson’s fitness-averse character to honor his passing:

Stefan Karl Stefansson was big part of my childhood, playing Robbie Rotten on LazyTown. I'm really devestated by the news of his passing. Once again, RIP to The Master Of Disguise pic.twitter.com/ySSfMEdPHq

One of my favourite shows as a kid was lazytown, and I always loved Robbie Rotten. Years later, the characters legacy was cemented with memes. Unfortunately though, Stefan Stefansson, the man who played him, has passed away. Rest easy Stefan, you were always number one pic.twitter.com/jFWERkzkzQ

As great as he was in his role, it's important to remember Stefan Karl was more than just Robbie Rotten. He was a father, husband and genuinely good person who just wanted to help others. He ran a charity against bullying and did volunteer work even after his diagnosis.

Very unfortunate news, today. Stefan Karl Stefanson, the actor who played Robbie Rotten, just passed away recently from cancer at the age of 43 by confirmed sources. Truly, this man will always be number one. Rest well, sir. pic.twitter.com/bXVVm9eQH8

RIP Robbie Rotten aka Stefan Karl StefanssonYour work over the years inspired millions of children and last year, your memes reminded us all to not take things too seriously.Truly, you were #1.RT to get this man on trending where he belongs! #RIPRobbieRottenpic.twitter.com/5PXDHrnPLe

So sorry to hear of the passing of Stefan Karl. Seeing Lazy Town for the 1st time was mesmerizing. There was nothing quite like it on TV. The puppets, colors, and visuals were off the chart. And Robbie Rotten was such an endearing villain. Our condolences #RobbieRotten

Farewell, Robbie Rotten. Hope you finally get to be lazy without those pesky kids exercising around you 24/7. You were a fantastic, funny character. RIP Stefan Karl Stefansson pic.twitter.com/A9GazKA0sL

I spent many hours with my younger siblings watching you years ago and ive lost count of how many times you made us laugh and smile uncontrollably. Thank you for all the joy you brought us and people everywhere. Rest in Peace Robbie Rotten. pic.twitter.com/0lXwMc7miX

Absolutely heartbroken that Stefán Karl Stefansson aka Robbie Rotten from LazyTown has passed away after losing his battle with cancer this morning. You will always be number one <3 pic.twitter.com/7Wf8VJoQSr